The field of this invention relates to testing apparatus and methods for evaluating sprayable water based compositions.
In recent years particularly as a result of the impact of the energy crisis, there has been a desire to apply in a single field pass a high concentration of sprayable solids or a mixture of different sprayable active agents so as to accomplish in single spraying operation a maximum amount of sprayed material application with a minimum consumption of energy.
Examples of composition which are sprayed at commercial rates include fertilizers, pesticides, herbicides, fungicides, and like biocides. As sprayed, a given formulation can be in the form of a suspension of solids in water (such as a colloidal suspension), and emulsion of oil or oil-like droplets suspended in a continuous aqueous phase, an aqueous solution, a mixture thereof, or the like. A large number of manufacturers of sprayable formulations exist and each manufacturer has his own manufacturing techniques, systems, and the like; not infrequently, a given manufacturer has trade secret information associated with his product or its manufacture. Commonly manufacturers of sprayable composition incorporate thereinto one or more surfactant additives to enhance the usability of the product. Commonly, sprayable compositions have come to be applied by farmers and professional spray applicators untrained in formulating chemical mixtures and these operators commonly endeavor to mix the product of one manufacturer with the product of another manufacturer in a single spray system; the spray applicator commonly does not know or even care about the exact chemical composition of the particular spray composition which he desires to utilize in his commercial operations. As a result of these variables, there has arisen in the art a need to evaluate a specific sprayable water based composition prior to its use in full scale commercial equipment. Such evaluations need to be carried out on a miniature scale and at low costs in a reliable and repeatable fashion. Unless such a preliminary evaluation is undertaken, the commercial sized batch of sprayable composition, in a given instance, may experience severe plugging of filter, or even the setting up of the entire batch in the reservoir, or like disaster so that an interruption in spraying is achieved to the great economic detriment of the user of the spray equipment.
Commercial spray equipment utilizes a very wide variety of nozzles, nozzle configurations, mixing conditions, inlet and outlet configurations, and the like. The equipment is not standardized with regard to sprayable mix recirculation requirements so that it is not possible to simply or easily determine conditions required in a given piece of equipment for minimum tank agitation for sprayability. Moreover, even a given water based sprayable composition can have different requirements for agitation from one piece of equipment to another because of inherent equipment operating variabilities.
The degree of chemical suspendability is no standardized in the biocide formulation industry. The extent of suspendability of a given type of formulation can vary from one manufacturer to another. Typically it is not possible for a user to determine the extent of agitation needed in a particular piece of commercial equipment which is sufficient to maintain a given sprayable composition in a homogeneous state for spraying. Furthermore condition required for homogeneity in a given sprayable composition may not be sufficient to maintain another type of sprayable composition even incorporating the same active ingredients.
The addition of more than one biocide or other material to be sprayed to a sprayable water based composition in a spray tank can create substantial mixing and compatability problems. Although manufacturers attempt to recommend all combinations of a given biocide formulation sold by them which they consider to be compatible (including combinations of products with other biocide manufacturers) such listing characteristically appear to omit certain combinations, perhaps because the manufacturer believes that such combinations should be avoided by a user, or perhaps because a complete list would be to exhaustive to be practical in the exigencies of the market place. Nevertheless, the operators of spray application equipment can either deliberately or inadvertently endeavor to combine various mixtures, including incompatible biocide formulations, resulting in disruptions in operations to their own great time and money and labor loss.
A simple reliable system for testing and evaluating sprayable compositions whether alone or in combination with other such compositions is needed in the art. However, so far is known, there has not previously existed either apparatus or method technology suitable for such miniature scale sprayability evaluation of sprayable water based compositions. The term "aqueous" as used herein is generally synonomous with "water based."